Roger Long wrote:
Dear Mrs. Manners,

What do you do when your marina neighbors are endangering other users,
your guests, and the metal parts of your boat?

The nimrod on the face of our pier,

A nimrod is a famous or very able hunter.

Here, I see nothing wrong with you disconnecting the power cord and
putting it on his deck. I doubt that if the live end fell into the
ocean, it'd stay live long as the breaker would then trip making your
scenario of many dead unlikely. I will, however, concede that is is
possible. How about instead we have this killing a scuba guy cleaning a
bottom?

If we want to get unlikely, then we can also say the live end falls into
the water and so charges the marina that all the zincs fail and boats
sink all around from the induced electrolysis.